This invention relates generally to vertical turbine pumps and more particularly to multistage turbine pump bowl assemblies capable of being assembled during installation in a deep well.
Multistage pump bowl assemblies used in very deep settings typically are of such great length that shipment and installation without incurring damage to such assemblies is a major problem. This is especially so for bowl assemblies designed to be installed in wells producing hot water or other hot pumpage. The impeller end play provided must be adequate not only for shaft stretch caused by hydraulic down thrust but must also be adequate to compensate for the differential thermal expansion of the column and shaft which occurs during and subsequent to the starting cycle. Bowl assemblies for very deep settings in hot water wells (e.g. 1200 feet at up to 375.degree. F.) commonly have as much as five inches of impeller end play. This can be provided only by using intermediate bowls with an elongated design. The high pumping head required for pumping from very deep wells requires a large number of pumping stages.
The combination of elongated intermediate pumping bowls, plus the use of many stages, causes the pump bowl assembly to be extremely long; and, as a consequence, they are difficult to install and often require special trailers and special highway permits for transport. Bowl assemblies are frequently shipped within a reinforcing pipe or strapped to a structural steel beam to prevent damage due to excessive bending stresses within the bowl assembly. These reinforcements are left in place at the well site while the bowl assembly is erected to a vertical position over the well. The extreme length of the bowl assemblies requires a very large installation rig with an excessive height.
The foregoing illustrates limitations known to exist in present multistage pumps for deep well applications, and it would be advantageous to provide an alternative directed to overcoming one or more of those limitations. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.